Some ramblings from when I was on the train earlier... Apologies for them being quite so rambling and I'm sure I've missed lots...
The empire varies a lot across the continent of anyaral. When describing culture and architecture I have generally focussed on the central empire, which I think of as covering those clans closest to gar loren. I'm not sure if that is an official term, but those clans certainly think a themselves as being a bit better than the more distant clans...
Beth has described a bit about the creche system, and it is in those central clans that that is most noticeable. It does to some extent enforce stratification of society, but young jenta who prove to be particularly adept are sometimes apprenticed outside the roles their creche would naturally put them into.
There is money within the empire. I'm not sure exactly what it looks like, but I could imagine the fubarnii being able to string it together somehow to make it easy to carry. Noble families within the major cities would see wealth as important, and would probably claim ownership of land within cities. Outside cities ownership of land would carry quite a responsibility, particularly in areas with devanu issues.
Taxes are dealt with at a clan level, but the clans are expected to pay their duties to the emperor. All clans must provide young jenta to join the knights as well as taxes in other forms to maintain the smooth running of the empire. I think jubal is right to assume those are relatively high. The fubarnii of the central empire sometimes grumble at paying to protect the distant clans, while the distant clans grumble at paying for luxuries for the emperor in the distant big cities, but the taxes are low enough not to cause much unhappiness as long as the devanu are largely kept at bay.
There have been times in the past where clans have upset the emperor and the knights have been withdrawn. The consequences were dire for the clans and they eventually rejoined the empire (albeit with increased taxes for future generations to cover the additional expenses of clearing out entrenched devanu nests etc).
All knights tend to speak quite a distinctive dialect as they are brought up very much as a family from jenta through to retirement. Most knights remain with the military even after they have been retired, but some will find a quiet place to retire, or lend their services to militia or even mercs.
I'm not sure at tom's comment that there are no other languages - some of the more distant clans do have their own languages, but the knights have done a lot to ensure that pretty much everybody can speak the language of the emperor.
Knights have a very strict remit never to get involved in inter-clan conflicts - this was not always the case and that caused a problem early after the formation of the empire. Maybe I'll detail that at some point, but for the moment the important factor is that if clans decide to attack each other then the knights will never get involved. They may be commanded to withdraw their services if a clan is found to be overstepping its bounds or behaving badly, but that is all.
I'm not sure what knights would do about bandits, but generally I think they would avoid getting involved and would leave that problem to the local militia.
On the economy... Land ownership varies between clans. The emperor leaves that to the clan councils to decide, and that depends a lot on the specific history of the clans, as well as what sort of use they have for land above ground.
And at Brandlin...
